Unpredictable Locations Research Articles

Modelling and simulation of anisotropic growth in brain tumours through poroelasticity: A study of ventricular compression and therapeutic protocols

Malignant brain tumours represent a significant medical challenge due to their aggressive nature and unpredictable locations. The growth of a brain tumour can result in a mass effect, causing compression and displacement of the surrounding healthy brain tissue and possibly leading to severe neurological complications. In this paper, we propose a multiphase mechanical model for brain tumour growth that quantifies deformations and solid stresses caused by the expanding tumour mass and incorporates anisotropic growth influenced by brain fibres. We employ a sharp interface model to simulate localised, non-invasive solid brain tumours, which are those responsible for substantial mechanical impact on the surrounding healthy tissue. By using patient-specific imaging data, we create realistic three-dimensional brain geometries and accurately represent ventricular shapes, to evaluate how the growing mass may compress and deform the cerebral ventricles. Another relevant feature of our model is the ability to simulate therapeutic protocols, facilitating the evaluation of treatment efficacy and guiding the development of personalized therapies for individual patients. Overall, our model allows to make a step towards a deeper analysis of the complex interactions between brain tumours and their environment, with a particular focus on the impact of a growing cancer on healthy tissue, ventricular compression, and therapeutic treatment.

Joint Task Offloading and Resource Allocation for Fog-Based Intelligent Transportation Systems: A UAV-Enabled Multi-Hop Collaboration Paradigm

Unmanned aerial vehicles (UAVs) have been widely used in Intelligent Transportation Systems (ITS) due to their rapid deployment and high mobility, which are considered as a promising solution to expand the scope of communication, especially in inaccessible areas. However, there is a lack of a universal and extensible multi-hop collaboration model in the existing research on UAV-involved ITS. In this paper, we innovatively introduce a novel UAV-enabled multi-hop collaborative fog computing (FC) system model, in which several moving UAVs with unpredictable locations provide effective and efficient communication and computation services for ground user equipments (UEs). With this model, we mathematically formulate a joint user association, UAV association, task offloading, transmission power, computation resource allocation, and UAV location optimization problem, which is a mixed integer nonlinear programming (MINLP) problem and challenging to deal with. To solve the non-convex problem, we propose a novel multi-hop collaborative algorithm to derive the optimal task offloading and resource allocation decisions for each UAV. Simulation results demonstrate the superiority of the UAV-enabled multi-hop collaborative FC system and validate the effectiveness of the proposed scheme.

The stabilization of visibility for sequentially presented, low-contrast objects: Experiments and neural field model.

In any environment, events transpire in temporal sequences. The general principle governing such sequences is that each instance of the event is influenced by its predecessors. It is shown here that this principle is true for a fundamental aspect of visual perception: visibility. A series of nine psychophysical experiments and associated neural dynamic simulations provide evidence that two non-stimulus factors, self-excitation and short-term memory, stabilize the visibility of a simple low-contrast object (a line segment) as it moves over a sequence of unpredictable locations. Stabilization was indicated by the very low probability of visible-to-invisible switches, and dependence on preceding visibility states was indicated by hysteresis as the contrast of the object was gradually decreased or increased. The contribution of self-excitation to stabilization was indicated by increased visible-to-invisible switching (decreased hysteresis) following adaptation of the visibility state, and the contribution of memory to stabilization was indicated by visibility "bridging" long blank intervals separating each relocation of the object. Because of the unpredictability of the relocations of the object, its visibility at one location pre-shapes visibility at its next location via persisting subthreshold activation of detectors surrounding the low-contrast object. All effects were modeled, including contributions from adaptation and recurrent inhibition, with a single set of parameter values.

Genetic Variants Leading to Urticaria and Angioedema and Associated Biomarkers.

Advances in next generation sequencing technologies, as well as their expanded accessibility and clinical use over the past 2 decades, have led to an exponential increase in the number of identified single gene disorders. Among these are primary atopic disorders-inborn errors of immunity resulting in severe allergic phenotypes as a primary presenting feature. Two cardinal aspects of type I immediate hypersensitivity allergic reactions are hives and angioedema. Mast cells (MCs) are frequent primary drivers of these symptoms, but other cells have also been implicated. Even where MC degranulation is believed to be the cause, mediator-induced symptoms may greatly vary among individuals. Angioedema-particularly in the absence of hives-may also be caused by hereditary angioedema conditions resulting from aberrant regulation of contact system activation and excessive bradykinin generation or impairment of vascular integrity. In these patients, swelling can affect unpredictable locations and fail to respond to MC-directed therapies. Genetic variants have helped delineate key pathways in the etiology of urticaria and nonatopic angioedema and led to the development of targeted therapies. Herein, we describe the currently known inherited and acquired genetic causes for these conditions, highlight specific features in their clinical presentations, and discuss the benefits and limitations of biomarkers that can help distinguish them.

A doubt–confirmation-based visual detection method for foreign object debris aided by assembly models

Foreign object debris (FOD) impacts significantly on the quality control during product assembly because it usually causes product failure. The vision-based method as a nondestructive and efficient technology has become an important approach to FOD detection. However, it faces two important challenges: (1) inexhaustible types (almost any object can become FOD) and (2) unpredictable locations (FOD can appear almost anywhere on surface of a product). Therefore, this paper proposes an FOD visual detection method based on doubt–confirmation strategy and aided by assembly models. Firstly, a coarse-to-fine method is designed for feature extraction and registration to align the test image with the reference image. Then, to solve the unpredictable location problem, different types of suspected FOD are extracted from the test image by a combined method of supervision and nonsupervision. Finally, to solve the inexhaustible type problem, an image comparison method based on a Histogram of Line Direction Angle is proposed, and re-recognition rules of suspected FOD established to complete the final discrimination. Experiments are conducted on a product with complex shape, and the results demonstrate the effectiveness and efficiency of our approach.

Grid graph-based large-scale point clouds registration

ABSTRACT Automatic registration of unordered point clouds is the prerequisite for urban reconstruction. However, most of the existing technologies still suffer from some limitations. On one hand, most of them are sensitive to noise and repetitive structures, which makes them infeasible for the registration of large-scale point clouds. On the other hand, most of them dealing with point clouds with limited overlaps and unpredictable location. All these problems make it difficult for registration technology to obtain qualified results in outdoor point cloud. To overcome these limitations, this paper presents a grid graph-based point cloud registration (GGR) algorithm to align pairwise scans. First, point cloud is divided into a set of 3D grids. We propose a voting strategy to measure the similarity between two grids based on feature descriptor, transforming the superficial correspondence into 3D grid expression. Next, a graph matching is proposed to capture the spatial consistency from putative correspondences, and graph matching hierarchically refines the corresponding grids until obtaining point-to-point correspondences. Comprehensive experiments demonstrated that the proposed algorithm obtains good performance in terms of successful registration rate, rotation error, translation error, and outperformed the state-of-the-art approaches.

Visual analytics identifies key miRNAs for differentiating peripancreatic paraganglioma and pancreatic neuroendocrine tumors.

Paragangliomas (PGL), a type of neuroendocrine tumor, pose a significant diagnostic challenge due to their potential for unpredictable locations and asymptomatic presentation. Misdiagnosis of peripancreatic PGLs, particularly as pancreatic neuroendocrine tumors (PANNETs), is a pressing issue as it can negatively impact both pre- and post-treatment decision-making. The aim of our study was to identify microRNA markers for the reliable differential diagnosis of peripancreatic PGLs and PANNETs, addressing a crucial unmet need in the field and advancing the standard of care for these patients. Morphing projections tool was used to analyze miRNA data from PGL and PANNET tumors present in the TCGA database. The findings were validated using two additional databases: GSE29742 and GSE73367. Our research uncovered substantial differences in the miRNA expression profiles of PGL and PANNET, leading to the identification of 6 key miRNAs (miR-10b-3p, miR-10b-5p, and the miRNA families miR-200c/141 and miR-194/192) that can effectively differentiate between the two types of tumors. These miRNA levels hold potential as biomarkers for improved diagnosis, offering a solution to the diagnostic challenge posed by these tumors and potentially improving the standard of care for patients.

Encountering a lateral pouch acute appendicitis in pediatric age group: case series study

Background: Facing lateral pouch appendicitis (LPA) is unusually encountered by pediatric surgeons, and usually, these cases carry intraoperative challenges due to their unpredictable location and are difficult to locate. Pediatric surgeons should be aware of this and anticipate encountering such cases. Diagnosis of acute appendicitis is based on clinical, laboratory, and imaging modalities. Moreover, the same diagnostic strategy is applied for LPA, but with more challenges since its location sometimes gives atypical presentations, with difficulty in finding the appendix during the ultrasonographic radiological imaging. Case Presentation: A total of three cases of acute appendicitis were presented, which were managed surgically. Intra-operatively, an appendix was found retroperitoneally with its base in the posterior wall of the cecum, while the terminal ileum was set in a retroperitoneal fashion alongside the lateral abdominal wall. This is an unusual location, which carries challenges during dealing with such cases. Conclusion: It was assumed that this is a considerable health concern that needs to be investigated. Clarifying the outcome in these cases, and describing the intraoperative findings, would help us understand the condition. Increase the awareness around the health care community, in order to manage these cases properly in terms of understanding the diagnostic challenges, and surgical interventions, and to prevent or decrease the intra-operative complications.

Collective Intelligence during Emergency Egress: The Mechanisms Underlying Altruistic Information Exchange

Understanding the human factors governing effective information exchange is increasingly indispensable for the design of day to day human-computer systems. Moreover, effective information exchange becomes a matter of life or death during emergency egress. The complexity of an unknown environment and the unpredictable locations of hazards often prevent evacuees from identifying safe routes. Successful evacuations from locations impacted by fire or earthquakes may depend on user-generated information to increase the chance of collective survival. The present paper employed multi-user virtual reality experiments and an online survey to investigate the mechanisms underlying social influence and collective intelligence during emergencies. Our results demonstrate that information sharing helps to reduce evacuation time and trajectory length. Participants also shared more when given incentives or when there was a lack of knowledge in the public information pool. This work provides further indications of how collective intelligence can be promoted and deployed during emergencies.

From separate items to an integrated unit in visual working memory: Similarity chunking vs. configural grouping

It is unclear whether sequentially presented items can be grouped into an ensemble by similarity chunking without the aid of the configural cue (e.g., Kanizsa figure). The current study systematically explored this issue by gradually weakening the configural cue until it was completely removed. The results showed that sequentially presented Pac-Men could be integrated into a Kanizsa figure for better memory only when they were successively presented in adjacent locations. When Pac-Men were presented at non-adjacent or unpredictable locations, they could be chunked by their orientation similarity (they all faced toward the fixation cross) to improve memory performance. Importantly, such orientation similarity alone was sufficient to evoke memory benefit, even when successively presented Pac-Men could not form a Kanizsa object structure. This memory benefit cannot simply be attributed to the statistic regularity or mental transformation based on the egocentric reference frame. However, the configural cue alone could not produce a memory benefit if these Pac-Men did not face toward the fixation cross. All of these results indicate that the memory benefit of sequentially presented items could occur by similarity chunking without the aid of the configural cue. The memory benefit based on the configural grouping was fragile when items were sequentially presented.

Sequential sampling from memory underlies action selection during abstract decision-making

The study of perceptual decision-making in monkeys has provided insights into the process by which sensory evidence is integrated toward a decision. When monkeys make decisions with the knowledge of the motor actions the decisions bear upon, the process of evidence integration is instantiated by neurons involved in the selection of said actions. It is less clear how monkeys make decisions when unaware of the actions required to communicate their choice-what we refer to as "abstract" decisions. We investigated this by training monkeys to associate the direction of motion of a noisy random-dot display with the color of two targets. Crucially, the targets were displayed at unpredictable locations after the motion stimulus was extinguished. We found that the monkeys postponed decision formation until the targets were revealed. Neurons in the parietal association area LIP represented the integration of evidence leading to a choice, but as the stimulus was no longer visible, the samples of evidence must have been retrieved from short-term memory. Our results imply that when decisions are temporally unyoked from the motor actions they bear upon, decision formation is protracted until they can be framed in terms of motor actions.

Radio Frequency Interference Signature Detection in Radar Remote Sensing Image Using Semantic Cognition Enhancement Network

Radio frequency interference (RFI) is a significant threat to accurate microwave remote sensing. The RFI signals manifest themselves in unpredictable locations and patterns in the image, which will cause measurement distortion, image degradation, or even lead to wrong retrievals of the geophysical parameters. Accurate detection of RFI artifacts is a prerequisite step to preserve the overall quality of remote sensing quality. In this paper, a semantic cognitive enhancement network for RFI signature detection is proposed. It employs an encoder-decoder architecture, which incorporates the atrous spatial pyramid pooling, Depthwise convolution, and self-attentional mechanism. Rather than detecting the existence of RFI artifacts for an entire image, the proposed scheme can realize RFI recognition in a pixel-wise manner without setting predefined thresholds. Extensive experimental results on diverse scenarios in Sentinel-1 images with various RFI types are provided, which demonstrates robust detection performance for both strong and weak interference without requiring a large number of training samples.

Multiple cues guarantee successful predation by a Neotropical wasp

Abstract Predatory social wasps are well studied in several aspects; however, foraging behaviour, especially that which takes place away from the nest at often unpredictable locations, or specialized behaviours to find and subdue prey are not well understood. In the Brazilian tropical savanna, the Polistinae wasp Brachygastra lecheguana is specialized in preying on some endophytic weevil larvae which develops inside floral buds. We hypothesized that these wasps utilize a combination of different mechanisms such as visual, chemical (odour) and possible tactile cues to find the weevil larvae. Using a combination of experimental manipulations (visual; chemical; visual/chemical) we tested the wasp’s ability to detect the endophytic larvae in the field. Additionally, we checked the ability of this wasp to detect vibrations produced by the weevils inside the buds. Our results suggest that the B. lecheguana wasp utilizes a sequence of eco-physiological mechanisms to find the endophytic larva inside floral buds: sight, smell, and perhaps touch. The use of multiple cues by this wasp guarantees such a high rate of predation on endophytic beetles that the wasp may have positive implications (reduction in weevils’ infestation) for the future of the host plant’s reproduction.

Peri-operative imaging techniques of the sentinel lymph node in veterinary oncology

When cancer cells spread through lymphatic vessels, the first lymph node they reach is the sentinel lymph node (SLN). Hence, if the SLN is free from metastatic cells, it can be assumed that further lymph nodes will be free of metastatic tumor cells too. If metastatic tumor cells are identified in the SLN, the patient is at risk of developing distant metastatic disease. In that case, further diagnostic and therapeutic steps are needed and the patient’s prognosis gets worse. The SLN can be located at an anatomically unpredictable location. This is likely due to lymphangiogenesis, which alters the normal lymphatic pathway and drains the metastatic cells to another lymph node than the expected anatomically closest one. Therefore, identifying the SLN by an accurate mapping technique is necessary. In this article, the existing techniques for SLN mapping are reviewed, and their use in human and veterinary medicine is compared.

Compacting oblivious agents on dynamic rings.

In this paper we investigate dynamic networks populated by autonomous mobile agents. Dynamic networks are networks whose topology can change continuously, at unpredictable locations and at unpredictable times. These changes are not considered to be faults, but rather an integral part of the nature of the system. The agents can autonomously move on the network, with the goal of solving cooperatively an assigned common task. Here, we focus on a specific network: the unoriented ring. More specifically, we study 1-interval connected dynamic rings (i.e., at any time, at most one of the edges might be missing). The agents move according to the widely used Look–Compute–Move life cycle, and can be homogenous (thus identical) or heterogenous (agents are assigned colors from a set of c > 1 colors). For identical agents, their goal is to form a compact segment, where agents occupy a continuous part of the ring and no two agents occupy the same node: we call this the Compact Configuration Problem. In the case of agents with colors, called the Colored Compact Configuration Problem, the goal is to group agents such that each group is formed by all agents having the same color, it occupies a continuous segment of the network, and groups of agents having different colors occupy distinct areas of the network. In this paper we determine the necessary conditions to solve both proposed problems. For all solvable cases, we provide algorithms for both the monochromatic and the colored version of the compact configuration problem. All our algorithms work even for the simplest model where agents have no persistent memory, no communication capabilities and do not agree on a common orientation within the network. To the best of our knowledge this is the first work on the compaction problem in a dynamic network.

Intraductal administration of N-methyl-N-nitrosourea as a novel rodent mammary tumor model.

Chemically induced animal models of breast cancer (BC) using N-methyl-N-nitrosourea (MNU) have been widely used in preclinical research. The conventional approach entails intraperitoneal (i.p) or intravenous injection of a carcinogen, leading to tumor induction at unpredictable locations. This study aimed to establish a modified MNU-induced rat mammary tumor model using intraductal (i.duc) administration and to evaluate its biological behavior, morphology, and response to chemotherapy drugs. In a pilot experiment, female Sprague-Dawley (SD) rats were injected with either i.duc MNU or vehicle to test the feasibility of this approach. We explored the appropriate dosage for stable tumor formation in pubescent female SD rats by testing a single i.duc dose of MNU (0.5, 1.0 and 2.0 mg) or vehicle. An i.duc injection of 20 µL (1 mg/per duct) MNU in the fourth rat mammary gland induced stable carcinomas in situ. Immunohistochemical (IHC) analysis showed positive expression of estrogen receptor (ER), negative expression of human epidermal growth factor receptor 2 (Her-2), and low expression of Ki-67. Histopathology revealed atypical hyperplasia in the mammary gland 4 weeks after carcinogen injection, developing into carcinoma in situ 5-6 weeks after treatment, with loss of α-SMA and calponin expressions during tumor progression. Albumin-bound paclitaxel (nab-PTX) was injected i.duc and intravenously (i.v) 5 weeks after administration of MNU. The tumor growth rate of the nab-PTX i.duc-treated group was lower than in the i.v and control groups. The number of TUNEL-positive apoptotic cells was significantly higher in the nab-PTX i.duc-treated group. Using i.duc MNU (20 µL, 1 mg) to establish a rat mammary tumor model resulted in a predictable location in the rat mammary gland and exhibited better consistency; i.duc administration of nab-PTX permitted a smaller drug dose, but produced a better drug response, than i.v injection.

The resurgence of Ebola disease outbreak in North-Kivu: viewpoint of the health system in the aftermath of the outbreak in the Democratic Republic of Congo

Ebola disease outbreak is a threatening killer that occurred at unpredictable locations and times. The horror of the 26 recorded outbreaks since 1976 had led to numerous skills centered on fighting the Ebola virus including the development of vaccines and drugs. To date, the Democratic Republic of Congo has been affected by twelve Ebola disease outbreaks. The index case of the twelfth Ebola outbreak declared on February 6, 2021, in North-Kivu province brings out a potential link between the twelfth Ebola outbreak and the tenth; the transmission of the Ebola virus from a survivor to his wife who received the vaccine against the Ebola virus and the disruptive infection and prevention control measures in the aftermath of an outbreak. This commentary highlights the importance of the application of the One Health approach, the implementation of long-term infection and prevention control surveillance, and the integration of the Ebola disease outbreak response into the existing health system. These measures should allow the early detection of infectious diseases and should minimize the occurrence of the next outbreaks in the previously affected region.

Prevalence and morphology of root canal isthmus in human permanent teeth using micro-computed tomography: A systematic review

Introduction: The isthmus is a communication between two or more root canals that contains pulp tissue. Its unpredictable location, variable prevalence, and anatomic complexity often result in challenging debridement. The knowledge of these factors may prove beneficial for successful endodontic treatment. The primary aim of this systematic review was to assess the prevalence and morphology of root canal isthmus (RCI) in human permanent teeth using micro-computed tomography (micro-CT) studies. The secondary aim was to assess the influence of demographic factors such as age, gender, and geographic region on the prevalence and morphology of the isthmus. Materials and Methods: An electronic search was conducted until January 2020. Studies published in the English language using micro-CT for the evaluation of isthmus prevalence and morphology were included. Sixteen articles met the inclusion criteria and were subjected to qualitative synthesis. Results: The prevalence of isthmus in the mesiobuccal root of maxillary first molars ranged from 8.9% to 70.8%, with maximum prevalence in the middle third of the root (49.50%–73%). The mesial root of mandibular molars had a prevalence ranging from 80.6% to 100% on full root analysis and 85%–88.89% in the apical third. Conclusion: The prevalence of RCI was higher in the mesiobuccal roots of maxillary molars and the mesial roots of mandibular molars, extending in the corono-apical direction with a complex and variable morphology. The influence of demographic factors on the prevalence of RCI could not be established clearly.

Reconsidering the ability of the stimulus unique features to capture attention: Evidence from change blindness and visual search paradigms.

In Experiment 1 (change blindness), participants received either intermixed or blocked presentations of two visual stimuli that contained several common (X) and unique (A or B) features. On the critical trial after exposure, the stimulus AX was presented but included an unexpected visual event (a change in the size of a stimulus feature). We found that participants readily detected the change when it involved an A-unique feature that had been preexposed intermixed. However, if the change involved an A-unique feature preexposed in blocks, or an X-common feature (preexposed either intermixed or in blocks), the level of the detections considerably decreased. In Experiment 2, after either intermixed or blocked preexposure to AX and BX, all the participants were instructed to search for an unrelated visual target item. In the distractor condition, during the development of the search task, the A-unique feature emerged at an unpredictable location that was different to that occupied by this feature during the preexposure. In the control condition, the target was presented on its own during the entire task. The presence of the A-unique feature only produced a detrimental effect on search performance when the AX and BX had been preexposed intermixed. These results are discussed as indicative of the intermixed preexposure schedule enhancing the ability of the stimulus unique features to capture involuntary attention. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

There is more to contextual cuing than meets the eye: Improving visual search without attentional guidance toward predictable target locations.

It is usually easier to find objects in a visual scene as we gain familiarity with it. Two decades of research on contextual cuing of visual search show that repeated exposure to a search display can facilitate the detection of targets that appear at predictable locations in that display. Typical accounts for this effect attribute an essential role to learned associations between the target and other stimuli in the search display. These associations improve visual search either by driving attention toward the usual location of the target or by facilitating its recognition. Contrary to this view, we show that a robust contextual cuing effect can also be observed when repeated search displays do not allow the location of the target to be predicted. These results suggest that, in addition to the mechanisms already explored by previous research, participants learn to ignore the locations usually occupied by distractors, which in turn facilitates the detection of targets even when they appear in unpredictable locations. (PsycInfo Database Record (c) 2020 APA, all rights reserved).